Method for treating fascioliasis



United States Patent Office Patented Dec. 2, 1969 Int. Cl. A61k 27/00;A01n 9/26 US. Cl. 424-127 3 Claims ABSTRACT OF THE DISCLOSURE Animalsinfected with fascioliasis are treated with orally administered,anthelmintically effective amounts of a composition having, as itsessential active component,

a biphenol of the formula OH on in which X is hydrogen or a halogen,such as bromide or chlorine, having an atomic weight between 35 and 81,and Y is a halogen also having an atomic weight between 35 and 81, orthe monophosphoric acid ester of such biphenol, or the sodium or otheralkali metal salts of such biphenol or its monophosphoric acid ester.The monophosphoric acid ester of 4,4,6,6-tetrabrom-0,0'- biphenol ispreferred, particularly in the form of its sodium salt, which can beconveniently obtained when a solution is formed of such ester and of anequivalent amount of sodium hydrogen carbonate.

The present invention relates generally to new antiparasiticcompositions, to new compounds contained in such compositions, tomethods for preparing these compositions and compounds, and to methodsfor combating internal parasites, particularly the liver-fluke (Fasciolahepatica).

Fascioliasis, liver rot, or liver-fluke infection is a disease fromwhich sheep and cattle particularly suffer, but by which otherwarm-blooded animals and even man may also be affected. The disease iscaused by the liverfluke (Fasciola hepatica), a parasite thriving in theliver and the :biliary ducts of the infected beings and there causingdamage by which the normal function of these organs is disturbed. Theafter-effect is a more or less serious decline in the general conditionof the animals, which may even lead to their death.

For combating this disease some new means have been suggested during thepast few years, for example hexaohlorophene or 2,2'-inethylenebis(3,4,6-trichlorophenol) and mofochlofeen or 'the monophosphoric acidester of hexachlorophene (which has been disclosed in British patentspecification No. 1,001,229). Although these new means have severaladvantages over the drugs previously used against fascioliasis, they arestill susceptible of improvement, particularly as regards theirtoxicity.

According to this invention, it has been found that biphenols of theformula in which X represents hydrogen or halogen and Y representshalogen, possess a pronounced activity against fascioliasis, and thatmost of the compounds included in the general formula show acomparatively low toxicity. Especially suitable are the compounds inwhich the halogen atoms have an atomic weight between 35 and 81.

It has further been found that the above compounds can be converted intotheir monophosphoric acid esters and physiologically acceptable saltsthereof which possess also a pronounced activity against fascioliasisand, more over, have better solubility properties. This is an advantagein working up the compounds into pharmaceutical compositions and inapplying them, especially in the treatment of sheep.

Some of the biphenols according to the above formula are known, as such,but not as remedies for fascioliasis. Specifically, compounds in which Xrepresents hydrogen and Y represents chlorine or bromide, and compoundsin which X and Y both represent either chlorine or bromine have beenmentioned in the US. Patent No. 2,487,799 and also in a paper by Paul B.Marsh et al. Ind. Eng. Chem, 38, 701 (1946). The compound in which bothX and Y represent chlorine has also been mentioned in an article by K.Okazaki et al., J. Pharm. Soc., Japan, 72, 1403 (1952). The compound inwhich X represents chlorine and Y represents bromine has been mentionedin a publication by Ph. W. Roberts-on et al., J. Chem. Soc., 101, 1973(1912), but that publication is very disputable and it is seriouslydoubted whether the authors did, in fact, obtain the described compound.The biphenols not mentioned in the preceding paragraph and thephosphoric acid esters of all the biphenols according to the aboveformula are new. They can be prepared by methods known per se foranalogous compounds. Thus, the unknown biphenols can be prepared byhalogenation of known compounds.

The monophosphoric acid esters can be prepared by a simple method thatinvolves treating the biphenol with phosphoryl chloride and hydrolyzingthe cyclic phosphorochloridate thus obtained, through the cyclicphosphate, into the monophosphoric acid ester according to theinvention. This method has been described for the production of themonophosphoric acid ester of hexachlorophene in the British patentspecification 1,001,229 mentioned before. However, in preparing themonophosphoric acid esters according to the invention it has been foundthat considerably better results than those described in this Britishspecification can be obtained if the conversion of the biphenol withphosphoryl chloride is carried out in the presence of pyridine. Thecyclic phosphates mentioned above as intermediates in preparing themonophosphoric acid esters are also new compounds, and can be isolatedif desired.

It has been found that the alkali metal salts of the new monophosphoricacid esters are particularly useful in combating liver-fluke infectionin sheep because of their relatively good solubility in water at'aphysiologicallyac ceptable pH.

For the preparation of antiparasitic compositions according to theinvention, the active components have to be made into suitableadministration forms such as tablets, pills, capsules, potions. For thatpurpose, the active component can be mixed with the usual pharmaceuticalcarriers as talc, magnesium, stearate, amylum, lactose andphysiologically acceptable solvents;

Particularly useful for the treatment of fascioliasis are tabletscontaining, in addition to the monophosphoric acid ester of thebiphenol, one equivalent of sodium hydrogen carbonate. It is alsopossible of course to mix the active components with feed or feedingredients and to administer the drug in this way.

It has been found that, in general, a single dose of about to about 30mg. per kg. of animal weight is suitable to cause a very satisfactoryand long-lasting reduction in the number of eggs present in the faecesof infected animals. It has further been found that said dose generallykills all mature live'r-flukes in experimental animals.

moles) and" I0 m1. of pyridine is"refluxe'd' for *14'hours, whereuponthe excess of phosphoryl chloride is removed carefully by evaporationunder reduced pressure. The residue is boiled for 15 minutes with 1.8 l.of water and 1 l. of 1 N sodium hydroxide. Thereupon, 200 ml. of 10 Nsodium hydroxide are added and boiling is continued for 2 hours.

After cooling, 300 ml. of concentrated hydrochloric acid are addedwhile" stirring, and the solution obtained is extracted with ethylacetate- The solvent is removed in vaeuo, yielding' the monophosphoricacid ester of 4,4, 6,6'-tetrabromo-0,0-bipheno1. v v

The product obtained maybe'further purified by dissolving the same in500 ml. of ethyl acetate, extracting this solution with 400 ml. of Watercontaining l6.8 grams of sodium hydrogen carbonate, acidifying'theaqueous layer, extracting the same again withethyl acetate,- and vfinally removing the solvent in'vacuo. Yield: 85%.

The above discussion of methods for the preparation 1 Approximately 6.5grams of 4,4',6,6'-tetrachlorO-0,0- biphenol are dissolved in 40 ml. ofl N sodium hydroxide and water is added to provide a total solution of325 ml. The solution obtained can be administered to animals forcombating fascioliasis.

EXAMPLE II 1.6 grams of 4,4,6,6'-tetrabromo-0,0'-biphenol are dissolved,while stirring and heating on a steam bath, in

10 ml. of Mulgofen EL-719 (a mixture of polyethylene others of hydroxyfatty acids). Thereupon, water is added to provide a total solution of80 ml. The solution obtained can be administered to animals forcombating fascioliasis.

EXAMPLE III A mixture of 4.2 grams of the monophosphoric acid ester of4,4-dibromo-0,0-biphenol and 2.1 grams of sodium hydrogen carbonate isdissolved in 150 ml. of water. The solution obtained can be used incombating fascioliasis.

EXAMPLE IV A mixture of 810 grams of 4,4',6,6-tetrabromo-0,0- biphenol,2770 grams of lactose and 120 grams of polyvinylpyrrolidone isgranulated in the usual way. Thereupon, 400 grams of sodium hydrogencarbonate, 140 grams of powdered talc, 70 grams of sodium stearate and190 grams of maize starch are added. The mixture is worked up in theusual way into 1000 oblong tablets of 4.5 grams each.

EXAMPLE V To a solution of 172 grams (0.5 mole) of 4,4dibromo-0,0'-biphenol in 1250 ml. of glacial acetic acid are added, all at once,120 ml. (1.5 moles) of sulphuryl chloride. The temperature is kept below35 C. by cooling. After the evolution of heat has ceased, the mixture isstill kept at 35 C. for 75 minutes. After cooling, the crystals formedare filtered. The mother liquor is diluted with water yielding morefinal product. The 4,4'-dibromo'-6,6'- dichloro-0,0-biphenol obtained.melts at 184-185" C. Yield: 99%.

EXAMPLE VI A mixture of 100.4 grams (0.2 mole) of 4,4,6,6'-tetrabr0mo-0,0-biphenol, 370 ml. of phosphoryl chloride (4 EXAMPLE VIIIn a similar way as described in Example VI, however, starting from thecorresponding biphenol, the monophosphoric acid ester of4,4,6,6'-tetrachloro-0,0f-biphenol is prepared. The product is obtainedin such apure state that the additional purification described in thepreceding example, is superfluous. Yield:

EXAMPLE VIII In a similar way as described in Example VII, themonophosphoric acid ester of 4,4-dibromo-0,0-biphenol is prepared.Yield: 98%.

EXAMPLE IX In a similar way as described in Example VII, themonophosphoric acid ester of 4,4-dibromo-6,6'-dichloro- 0,0'-bipheno1 isprepared. Yield: 99%.

The purity of the monophosphoric acid esters obtained according toExamples VI through IX is checked by means of potentiometric titration.

EXAMPLE X Rats, in which liver-flukes are implanted subcutaneousy, aretreated with a single dose of the compounds according to the presentinvention. Three days after treatment the percentage of killedliver-flukes is determined. Some test-animals are not treated in orderto serve as controls. The method used is analogous to that described byE. Lienert, Exp. Parasitol., 10, 223 (1960).

The results obtained are summarized in the following table:

Percentage of killed liver-flukes Dosage, mgJkg.

Compounds administered 5 10 20 Controls Biphenols according to thegeneral formula in whic 1 1. (X=Cl, Y-Cl) 60 93 12 2. =Br, =Br) 57 59 9414 3. (X=Cl, Y=Br) 48 76 17 4. Monophosph. acid est. of 2 64 97 12 5.Mouophosph. acid est. of 3 52 71 11 EXAMPLE XI EXAMPLE XII A sheep, thefaeces of which contain 20 liver-fluke eggs per gram, is treated with asingle dose of 28 rug/kg. of

the monophosphoric acid ester of 4,4'-dibromo-0,0-biphenol in the formof a solution prepared according to Example III. Two weeks aftertreatment the faeces of the sheep are free from eggs of the parasite.

EXAMPLE XIII Twelve sheep, the faeces of which contain on an average 73liver-fluke eggs per gram, are treated each with a single dose ofmg./kg. of 4,4'-dibromo-6,6-dichloro- 0,0-'biphenol in the form of asolution analogous to that described in Example I. Two, three and fourweeks after treatment, the faeces of the sheep are free from eggs of theparasite.

EXAMPLE XIV A mixture of 580 grams of the monophosphoric acid ester of4,4,6,6-tetrabromo-0,0'-biphenol, 3000 grams of lactose and 120 grams ofpolyvinylpyrrolidone is granulated in the usual way. Thereupon 300 gramsof sodium hydrogen carbonate, 140 grams of powdered talc, 70 grams ofsodium stearate and 290 grams of maize starch are added. The mixture isworked up in the usual way into 1000 oblong tablets of 4.5 grams each.

EXAMPLE XV Fifteen sheep, the faeces of which contain considerableamounts of liver-fluke eggs and which are consequently strongly affectedwith fascioliasis, are treated with oblong tablets prepared according toExample XIV. The individual single dosage amounts to 16 mg./kg. bodyweight. Two and three Weeks after treatment the faeces of the animalsare tested again for the occurrence of liver-fluke eggs therein. Itappears that the excretion of such eggs has completely stopped.

What is claimed is:

1'. A method of treating animals infected with fascioliasis consistingessentially in orally administering to an animal infected withfascioliasis anthelmintically effective amounts of a composition having,as its essential active component, a substance selected from the groupconsisting of a biphenol of the formula I Y Y in which X is selectedfrom the group consisting of hydrogen and halogen having an atomicweight between approximately and 81, and Y represents halogen having anatomic weight between approximately 35 and 81, monophosphoric acid esterof said biphenol and physiologically acceptable alkali metal salts ofsaid biphenol and of said ester thereof.

2. The method according to claim 1, in which said substance is selectedfrom the group consisting of the monophosphoric acid ester of4,4',6,6'-tetrabromo-0,0-biphenol and the physiologically acceptablealkali metal salts thereof.

3. The method according to claim 1, in which said composition contains,in addition to said selected substance, an equivalent amount of sodiumhydrogen carbonate.

References Cited UNITED STATES PATENTS 3,352,751 11/1967 Akkerman et al16753 2,353,724 7/1944 Gump 260620 3,082,151 3/1963 Meiser et al. 167-533,082,151 3/ 1963 Meiser et al 424-347 FOREIGN PATENTS 758,595 10/ 1956Great Britain.

OTHER REFERENCES The Merck Index, 7th ed., 1960, p. 946. The MerckManual, 9th ed., 1956, p. 1055.

Chemical Abstracts, vol. 56, 1962, pp. 4661-4663.

FRANK CACCIAPAGLIA, JR., Primary Examiner Us. 01. X.R. 424 217, 347

